JPH0727635B2 - Method of manufacturing magnetic recording medium - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a magnetic recording medium having a ferromagnetic metal thin film as a magnetic recording layer.

2. Description of the Related Art In recent years, there have been remarkable advances in increasing the density of magnetic recording, and there is a strong demand for the practical application of magnetic recording media using a ferromagnetic metal thin film as a magnetic recording layer.

What is used as a ferromagnetic metal thin film is Co-ni-
O-based obliquely evaporated films and perpendicularly magnetized films such as Co-Cr, which are premised on a recording wavelength of 1 μm or less, and therefore spacing loss during recording / reproduction cannot be ignored, so direct sliding with the magnetic head is not possible. As a premise, there is a problem of wear.

In order to solve this problem, many experiments have been conducted and various improvement proposals have been made.

It is broadly classified into a method of providing a protective film, a method of interposing a lubricant between the head and the medium, and a combination thereof. Among them, the reaction film utilizing plasma activity such as plasma polymerization film is used. It is considered promising to form a film on a ferromagnetic metal thin film.

FIG. 3 is a main part configuration diagram of an example of an apparatus used for forming a protective film using plasma.

In FIG. 3, 1 is a vacuum container, 2 and 3 are discharge electrodes, and 4 is a material to be processed which becomes a magnetic recording medium, and it comprises a polymer film 5 and a ferromagnetic metal thin film 6. Reference numeral 7 is a gas introduction port, 8 is an exhaust hole, and 9 is an insulation introduction terminal.

Using the apparatus shown in FIG. 3, a carbon film CH ₄ , C ₂ H ₆ etc. alone or a mixed gas using Ar etc. as a carrier gas is introduced onto the ferromagnetic metal thin film 6, and a high frequency of 13.56 MHz is used, for example. It is common to generate glow discharge and form with that energy, or to form a plasma polymerized film using styrene, perfluorocyclobutane, etc. There are two types that keep you in motion. Especially when processing in a moving state, the film formation speed is the key to practical use, and while devising ways to increase the speed, the material to be processed is cooled to increase the plasma power, An example is changing the frequency for exciting the plasma to find the maximum area.

Problems to be Solved by the Invention However, with the above-mentioned configuration, the film formation speed is still low and high speed is required for application to a tape-shaped medium as a magnetic recording medium.

The present invention has been made in view of the above circumstances, and particularly provides a method capable of forming a carbon film on a ferromagnetic metal thin film at a high speed.

Means for Solving the Problems In order to solve the above problems, a method for producing a magnetic recording medium of the present invention is to dispose a graphite electrode kept at a negative potential with respect to a substrate and introduce a hydrocarbon gas, A carbon film is formed on the surface of the ferromagnetic metal thin film by generating glow discharge.

Action The method for producing a magnetic recording medium of the present invention has the above-described structure, in which hydrocarbons are decomposed by glow discharge and free carbon participates in film formation, and hydrogen produced by decomposition reacts with graphite. Since the sputtering is performed at a high speed by the characteristic sputtering mechanism, the carbon film can be formed also by the sputtering of graphite, and it is not necessary to use argon or the like for both of them, so that a high-quality carbon film is formed at a high speed.

EXAMPLES Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is an enlarged sectional view of a magnetic recording medium obtained by the present invention. In FIG. 1, 10 is a polymer film, 11 is a ferromagnetic metal thin film, and 12 is a carbon film.

FIG. 2 is a configuration diagram of essential parts of a carbon film forming apparatus used for carrying out the present invention. In FIG. 2, 13 is a vacuum container and 14 is a material to be treated, which is composed of a polymer film 15 and a ferromagnetic metal thin film 16. Reference numeral 17 denotes a graphite electrode, which is kept at a negative potential with respect to the ferromagnetic metal thin film 16. Reference numeral 18 is a high-frequency electrode, and 19 is a gas introduction nozzle, which has a plurality of holes arranged on a disc. 20 is an insulation introduction terminal. Reference numeral 21 is an exhaust hole communicating with the vacuum exhaust system.

Using the apparatus shown in Fig. 2, Co-Ni (Ni20wt) was added to 1 x 10 ^-5 (Torr) oxygen on a polyethylene terephthalate film with a thickness of 10.5 μm along a cylindrical can with a diameter of 1 m.
%) By electron beam evaporation, film thickness 0.14 (μm), coercive force 10
The material to be treated on which a 50 (Oe) ferromagnetic metal thin film is formed is
While moving at min, 90Å carbon film was formed.

While introducing CH ₄ gas at 0.4 / min, injecting 1.9 KW of 29 KHz high frequency at 0.13 Torr to generate glow discharge,
A carbon film was formed. In graphite, the ferromagnetic metal thin film was kept at a potential of -660V with respect to the ground potential. The tape on which a carbon film was formed under these conditions was designated as Tape A.

_{Also, C 2 H 6 + H 2} ( flow ratio of 4: 3) was 0.56 / min introduced in total, a 13.56MHz high frequency and 0.5KW introduced at 0.2 Torr, distribution of carbon film obtained by -960V applied to the graphite The obtained tape was used as tape B.

As a comparative example, CH ₄ + Ar (flow ratio 1: 2) gas is 0.5
Tape C was prepared by introducing a high frequency of 13.56 MHz at 0.22 Torr at 2.7 KW and introducing a carbon film.
The moving speed of the material to be treated was 0.9 m / min under the above conditions for obtaining the carbon film 90Å to obtain the tape C.

Images of tapes A, B, and C recorded with sendust heads at 3600 rpm were monitored in a static state and the time until noise was compared was 450 minutes, 490 minutes, and 19 minutes, respectively.
It was a minute. The measurement environment is 40 ° C and 20% RH.

The carbon film of the present invention is presumed to be diamond-like by Raman spectroscopy and the like, and is therefore characterized by having excellent durability as described above, and the film forming rate is 10 times higher than that of the conventional one. Now, it can be said that the protective film is extremely fast in terms of durability.

In the examples of the present invention, CH ₄ and C ₂ H ₆ were used, but other hydrocarbons alone, a mixed gas, or a system to which H ₂ gas is added has the same effect.

Also, as a ferromagnetic metal thin film to form a carbon film
A Co-Ni-O film was used, but other Co-O, Co-Fe-O, Co-C
r, Co-Ti, Co-Rh, Co-Ru, Co-Pt, Co-Mo, Co-Mg, Co-W,
It may be Co-Ta or the like.

EFFECTS OF THE INVENTION As described above, according to the present invention, there is an excellent effect that a diamond-like carbon film can be formed on a ferromagnetic metal thin film at a high speed, and there is also an excellent effect that the obtained film has a large protective effect.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of an example of a magnetic recording medium manufactured by the method of the present invention, FIG. 2 is a configuration diagram of a main part of a manufacturing apparatus used for carrying out the present invention, and FIG. 3 is used in a conventional manufacturing method. It is a principal part block diagram of the manufacturing apparatus which is. 10 …… Polymer film, 11 …… Ferromagnetic metal thin film, 12 ……
Carbon film, 14 ... Material to be treated, 17 ... Graphite electrode, 18 ... High frequency electrode, 19 ... Gas introduction nozzle.

Claims (1)

[Claims] 1. A carbon film is formed on the surface of a ferromagnetic metal thin film by disposing a graphite electrode kept at a negative potential with respect to a substrate and introducing a hydrocarbon-based gas to generate glow discharge. A method for manufacturing a characteristic magnetic recording medium.